Validation of the Lactate Plus lactate meter for use in horses.
Authors:Allison Fisher, Ashlee Hauss, Cortney Stablein
- Yvette Nout-Lomas, Assistant Professor- Equine Sciences, California State Polytechnic University, Pomona
- Holly Greene, Equine Research Technician, California State Polytechnic University, Pomona
Hypothesis: The hand-held Lactate Plus lactate meter (LPlus), developed for use in humans, provides dependable results when used in horses. Rationale: Since it is common to measure blood lactate concentrations [Lac] in horses during exercise and in clinical settings, the equine industry has a need for a convenient, rapid, and reliable method of measuring [Lac]. In healthy horses [Lac]=<1.5mmol/L. Methods: Five adult horses underwent a 4-week training program that consisted of 3 exercise bouts/week. Before and after this training program horses were subjected to a standardized exercise test (SET). SETs were conducted on an equine treadmill with horses running at 4.0m/s for 5 minutes followed by 5-minute 0.5m/s increments after that. Blood samples were collected before each increase in speed until [Lac] reached ≥4mmol/L and then the SET was stopped. Blood was analyzed at the time of collection using the LPlus, which was calibrated prior to each SET, and plasma was stored for later biochemical analysis. Heart rate and body temperature were also measured. Bland-Altman analysis was used to compare the values from the LPlus to the gold standard biochemical assay. Repeated measures ANOVA was used to compare the data between the SETs. Results: 95% of [Lac] were within average+/-1.96SD (or 95%CI), which according to Bland-Altman is within acceptable limits of agreement. The LPlus tended to overestimate [Lac] by 0.39mmol/L, however this bias was not statistically significant (p<0.001). Over the course of the SETs all horses showed an increase in heart rate, packed cell volume and [Lac]. All horses showed an increased velocity at which [Lac]=4mmol/L in SET2, consistent with improved fitness. Principal Conclusions: The LPlus can reliably be used to determine [Lac] in horses with [Lac] ranging from 0– 8mmol/L. Further research should be done to determine how reliable this technique is for horses with [Lac] >8mmol/L.